Fuel injection pump



Aug 1941- E. M. PURDY 2,251,552 FUEL INJECTION PUMP Original Filed Nov. 7, 1935 56 f a .l. .52

14 75 5, ,fifd A? //6 //6 -/6 -/a 00 I l W170 /& I J M I 62% za L22 24 24 7 7 V- 36 \J \Y) 4 42 iTE'. INVENT'OR i 3 v EVERETT M. PURDY I BY HIS ATTORNEYS Patented Aug. 5, 1941 FUEL INJECTION PUMP Everett M. Purdy, New Canaan, Conn.,- assignor to Eisemann Magneto Corporation, New

N. Y., a corporation of New York application November I, 1935, Serial No. Divided and this application January Original 48,744.

York,

18, 1938, Serial No. 185,587

12 Claims. (Cl. 103-41) This invention relates to fuel injection pumps for internal combustion engines and more particularly internal combustion engines firing partially or wholly bythe heat of compression and it is an object of this invention to provide an improved device of the type described in which the volume of fuel supplied to the engine cylinders is regulated by venting fuel from in front of the pump plungers throughout the o'ompres-' sion stroke of the plunger and the device is of such construction that a-single valve may serve to control the venting of .fuel from in front of a plurality of .pump plungers without the fuel being forced-from in front of one plunger to in front of-otherplung'ers. 1 Y I In the drawin -r f Fig. -1 is a; vertical sectional view of a fuel injection pump in accordance with-this invention; I

Fig 2 is --a -j partial vertical sectional view,

, drawn to a; larger sea the control valve Shown ..pl p ofJFi'g. 1;

Fig. 3,isa, horizontalsectional view taken as on line 3-4 of Fig.1,2; and

Fig. 4 is a partial i-vertical sectional view of a plunger of the pump shown in Fig. 1.

As shown in the drawing, a fuel injection pump constructed in accordance with this invention comprises a casingfconsisting'of' a substantially cylindrical portion I 'having a flange 2 at one end 1 thereof. by which itis-securedto' a correspondingly shaped flanges a'second casing portion 4. The casing portion tis also provided with an annular flange, 5 which-fits within an opening 6 of the casing portion-T8; Screws I threaded into openings in the flange. 3 secure the casing sections together. The c'asingsection I is provided with a plurality of bores or cylindrical chambers 8, one fol-"each of thecylinders of the engine with which the pump is to be used. The construction shown in-the drawing is arranged for four of such chambers 8' placed with their axes spaced uniformlyi'n a circle about the central axis of the cylindrical portion l of the casing. The bores 8 vary in diameter at different portions of their length and in each 'bore'8 there is a tubular plunger follower lll'which has one end thereof closed-and which isslidably mounted in that portion ofthebore 8 adjacent the casing portion 4 and held against turning by a pin l2 which engages in a slot l4 formed in the side wall of the plunger follower. In each bore 8 there is also fitted a fuel plunger bushing or cylinder l6 which extends into the follower l0 and is of greater diameter at one end so as to engage with a shoulder l8 formed in the bore 8. The bushing l6 has a cylindrical opening or bore of uniform diameter throughout its length in which is slidably mounted the fuel plunger or piston 20. The plunger 20 at one end extends beyond the bushing [6 toengage the closed end of the follower Ill and its projecting end is provided with a spring seat 22 held in position by a spring wire 24 which engages in I a groove 26 in the plunger. The spring seat 22 serves as a seat for a spring 28 which is confined between the spring seat and a shoulderiforme'd in the bore 8 and which holds the end of the plunger 20 in engagement with the follower l0.

To operate the follower Ill and fuel plunger 20 the'lower end of the follower I0 is recessed to receive a roller 30 mounted on a pin 32 which extends through a transverse opening in the.

follower Ill and is held in position by a spring wire 34 engaged in notches in the pin 32 and a groove in the follower l0. The roller 30 is positionedto be engaged by a cam 36 formed integral with a gear 38 on the end of a shaft 40 which is mounted in the casing portion 4 and arranged to be driven in suitable manner from the engine with which the pump is associated. The shaft 40 extends through a cylindrical boss 4* which is formed integral'with the casing portion 4 androtatably mounted in a bracket suitably supported fromthe engine. A set screw, threaded into the bracket and engaging in a groove 4' formed in the boss 4" secures the pump casing to the bracket and-permits of rotative adjustment of the casing with respect to the bracket. To provide for the free operation of the gear 38 and cam 36 the gear wheel is supported by a thrust bearing 42 and the shaft 40 is guided by a ball bearing 44, an oil seal 46 being provided between the bearings 44 and the'face of the casing portion 4 in order to'prevent leakage of the lubricant along the shaft-40.

Threaded into the bore 8 at the free end of the casing'section I is a plug 48 which retains the plunger bushing l8 iniits position in the bore 8 and which is provided with a, central opening having a portion thereof shaped to provide a seat for the check valve 50. The plug 48 above the valve 50 is bored to receive a coupling member 52 having a central opening which communicates with a chamber above the valve 50 and is enlarged immediately above the valve 50 to receive a spring which returns the check valve 50 to its seat. A second coupling member 58 cooperates with the coupling member 52 in securing the end of a pipe 58' which connects the individual plunger bore to a, cylinder of the motor with which the pump is associated.

At the axis of the casing portion I and equidistant from all of the plunger bores 8 is a bore having an inner portion forming a chamber 68 which is in communication through an opening 62 with a fuel container. Above the chamber 68 the bore is shouldered and has seated therein a plug I43 having a central bore II4. A screw threaded plug 66, also having a central bore, serves to secure the plug I43 in position and mounted in the bores of the plugs 86 and I43 and having threaded engagement with the plug 66 is a fuel supply controlling valve 15. Passage or ports II6 extend radially from the bore II4 of the plug I43 to the bores for all the pump plungers in the pump plunger bushings I6 and ports or passages 88 extend from the pump plunger bores to a, chamber H8 which surrounds the plug I43 and which is in communication through port I28 with the source of fuel supply. The valve I is grooved, as at I48, and its inner end portion I4I of full diameter is shaped to provide a flat inclined surface I42 on one side of the valve which cooperates with a shoulder in the bore I I4 in controlling the passage of fuel through the bore I I4 to the chamber 88. Controlling a port or passage common to all pump sections of the device prevents slight irregularities in the port sizes from affecting the amount of fuel supplied to the engine cylinders. In this construction the pump plungers 28 are grooved, as at I42 and I44, and have an axial port 84 extending from the upper ends of the plungers to transverse ports I46 and I48 communicating with the grooves I44 and I42, respectively.

In the operation of this device when a plunger 28 is retracted fuel is I28, chamber H8 and port 88 to the pump plunger bore at the groove I 44, then through the transverse port I46 and the axial port 84 to the chamber above the pump plunger. The port I48 and the groove I 42 of the pump plunger are at this time closed by the bushing I6 and the upper end portion of the plunger, which is of full diameter, seals the port IIG. As the plunger is raised the port 88 is cut off and communication between the groove I44 of the plunger and the bore for the valve is established through the port I I6 so that as fuel is forced from the chamber above the plunger 28 past the check valve 58 to an engine cylinder, fuel is also permitted to pass through the port 84 and port I46 to the port II6, past the inclined surface I42 of the valve 15 and through the bore 4 to the fuel chamber 68 which is in communication through the port 62 with the fuel supply.

As a pump plunger is raised to its uppermost position communication is established between the groove I42 on the pump plunger andport 88 leading to the chamber H8 so that as the plunger attains its uppermost position the pressure above the plunger is vented through the port -84, port I48 and port 88 to chamber II8, releasing the pressure above the pump plunger and cutting oil? the supply of fuel to the engine cylinder. During the return movement of the plunger from its uppermost position some fuel may be supplied to the chamber above the plunger from the fuel supply chamber II8 through the port 88, port I48 and port 84 and also from the fuel chamber 68 past the valve 15 and through ports I I6, I46 and 84. Port 88, however, is cut off very shortly after the return movement of pending application,

supplied through port the plunger 28 starts and the port H6 is subsequently cut off and thereafter remains cut off, port 88 being reopened again upon movement of the plunger 28 to its lowermost position for the passage of fuel from the chamber H8.

In this construction it will be noted that the fuel control valve I5 does not control the sup ply of fuel to the bore for the pump plunger but controls a by-pass or waste passage which vents a portion of the fuel from the bore for the pump plunger as the pump plunger is operated to force the fuel to the engine cylinder, the valve I5 serving to control this discharge from the bore for each pump plunger. In this construction, also, instead of having the pump plunger maintained at its uppermost position while each of the other pump plungers is operated the operating cam is so shaped that the pump plunger is returned to its lowermost position after each operation and remains in the lowermost position while-each of the other pump plungers is operated. Thus, as each plunger 28 is on its delivery or outward stroke, the remaining plungers are positioned so that the ports '6 leading thereto are closed by the upper end portions of these plungers and the discharge of fuel except to the engine cylinder corresponding to the operating plunger or past valve I5 is prevented.

While the valve I5 has been shown and described as threaded into the plug 66 and manually adjustable it is to be understood that the valve I5- may be slidably mounted in the plug and controlled by a governor as shown in my co- Serial No. 48,744, filed Nov. 7, 1935, which resulted in Patent No. 2,166,876, issued July 18, 1939, and of which application this application is a division.

I claim 1. In a fuel injection pump, a casing having a plurality of pump plunger bores, a valve bore, a common discharge port and ports and passages connecting said bores, for supplying fuel to the pump plunger bores and for connecting said plunger bores to said common discharge port, pump plungers in said plunger bores, means for operating said plungers to force fuel to individual engine cylinders and a valve in said valve bore controlling said common discharge port for venting fuel from in front of all plungers during the pumping strokes thereof, said plungers having intermediate portions closing the fuel supply ports during the pumping strokes of said plungers and end portions closing the ports to said discharge valve in the retracted positions of said plungers and said plunger operating means positioning each plunger in retracted position after an operation thereof prior to the operation of the succeeding plunger.

2. In a fuel injection pump, a casing having a plurality of pump plunger bores, a valve bore, a common discharge port and ports and passages connecting said bores, for supplying fuel to the pump plunger bores and for connecting said plunger bores to said common discharge port, pump plungers in said plunger bores, means for operating said plungers to force fuel to individual engine cylinders and a valve in said valve bore controlling said common discharge port for venting fuel from in front of all plungers during the pumping strokes thereof, said plungers having intermediate portions closing their fuel supply ports during their pumping strokes and opening said fuel supply ports to stop fuel injection and end portions'closing the ports to said discharge valve in the retracted positions of said plungers,

and said plunger operating means positioning each plunger in retracted position after an operation thereof prior to the operation of the succeeding plunger. i

3. In a fuel injection pump, a casing having a plurality of pump plunger bores, a valve bore, a common discharge port and ports and passages connecting said bores, for supplying fuel to the pump plunger bores and for connecting said plunger bores to said common discharge port,

pump plungers in said plunger bores, means for operating said plungers to force fuel to individual engine cylinders and a valve in said valve bore controlling a common discharge port for venting fuel from in front of all plungers during the pumping strokes thereof, said plungers having portions controlling the supply of fuel to said plunger bores and the termination of fuel injection and being extended to close the ports leading to said discharge valve in the retracted positions of said plungers, and said Plunger operating means positioning each plunger in retracted position after. an operation thereof prior to the operation of the succeeding plunger.

4. In a fuel injection pump having a plurality of pump plunger bores, a valve bore, a common discharge port and passages for the supply of fuel to said plunger bores and the discharge of fuel from said plunger bores to individual cylinders of an engine, pump plungers in said Plunger bores for forcing fuel from said bores to the corresponding engine cylinders, means for operating said plungers, means for venting fuel from in front of said plungers to said common discharge port, a valve in said'valve bore controlling the venting of fuel through said common discharge port from in front of all plungers during the pumping strokes thereof and means for preventing flow to said plunger bores by said plungers.

5. In a fuel injection pump having a plurality of pump plunger bores, a valve bore, a common discharge port and passages for the supply of fuel to said plunger bores and the discharge of fuel from said plunger bores to individual cylinders of an engine, pump plungers in said plunger bores for forcing fuel from said bores to the corresponding engine cylinders, means for operating said plungers, means for venting fuel from in front of said plungers to said common discharge port, a valve in said valve bore controlling the venting of fuel through said common discharge port from in front of all plungers during the pumping strokes thereof and means for preventing flow of fuel from in front of one plunger to in front of another plunger by said second plunger.

6. In a fuel injection pump having a plurality of pump plunger bores, a valve bore, a common discharge port and passages for the supply of fuel to said plunger bores and the discharge of fuel from said plunger bores .to individual cylinders of an engine, pump plungers in said plunger bores for forcing fuel from said bores to the corresponding engine'cylinders, means for operating said plungers, means for venting fuel from in front of said plungers to said common discharge port, a valve in said valve bore controlling the venting of fuel through said common discharge port from in front of all plungers during the pumping strokes thereof and means on said plungers for preventing flow of fuel from in front of one plunger to in front of another plunger.

'7. In a fuel injection pump having a plurality of pump plunger bores, a valve bore, a common discharge port. and passages for the supply of fuel to said plunger bores and the discharge of fuel from said plunger bores to individual cylinders of an engine, pump plungers in said to the corresponding engine cylinders, means for operating said plungers, means for venting fuel from in front of said plungers to said common discharge port, a valve in said valve bore controlling the venting of fuel through said common discharge port from in front of all plungers during the pumping strokes thereof and means on each plunger for preventing flow of fuel to in front of said plunger from in front of all other plungers.

8. In a fuel injection pump a casing having a plurality of pump plunger bores, a valve bore, a common discharge port and ports and pas-'- sages connecting said valve and plunger bores I said common discharge port and a valve controlling the venting of fuel through said common discharge port from in front of all plungers during the pumping-strokes thereof and means on each plunger eflective when said plunger is inoperative to prevent flow of fuel from said valve bore to said plunger bore.

9. In a fuel injection pump; a casing having a plurality of pump plunger bores, a valve bore, a common discharge port and ports and passages connecting said valve and plunger bores and for the passage of fuel to said plunger bores and from said plunger bores toindividual engine cylinders, pump plungers in said plunger bores, means for operating said lungers to force fuel a to said individual engine cylinders, means for venting fuel from in front of said plungers to said common discharge port and a valve controlling the venting of fuel through said common discharge port from in front of all plungers during the pumping strokes thereof, said plungers having portions closing the passages from said plunger bores to said valve bore in the retracted position of said plungers to prevent flow of fuel from said valve bore to said plunger bores.

10. In a fuel injection pump a casing having a plurality of pump plunger bores, a valve bore,

a common discharge port and ports and passages connecting said valve and plunger bores and for 85 the passage of fuel to said plunger bores and from said plunger bores to individual engine cylinders, pump plungers in said plunger bores, means for operating said plungers to force fuel to said individual engine cylinders, means for 60. venting fuel from in front of said plungers to said common dischar e port and a valve controlling the venting of fuel through said common discharge port from in front'of all plungers during the pumping strokes thereof, said plungers having ports for venting fuel from in front of said plungers to stop the flow'of fuel to the enne cylinders and end portions effective in the retracted position of said plungers to prevent flow the bore of an operating plunger.

plunger bores for forcing fuel from said bores of fuel to the bores of inactive plungers from fuel from said plunger bores to individual cylinders of an engine pump, plungers in said plunger bores for forcing fuel from said bores to the corresponding engine cylinders, means for operating "said plungers, said means operating each plunger individually and leaving the remaining plungers in the retracted position, means for venting fuel from in front of each plunger. during the operating stroke thereof to said common discharge port and a valve controlling said port, said plungers preventing flow of fuel from in front of an operating plunger to in front of the remaining plun ers.

12. In a. fuel injection pump a casing having a plurality of pump plunger bores, a valve bore, a common discharge port and fuel ports and passages therein, pump plungers in said plunger bores, means for operating said plungers to force fuel through said ports and passages to individual engine cylinders and to said common discharge port and a valve in said valve bore conplunger bores.

EVERETT M. PURDY. 

